This invention relates to a method of monitoring for the formation of a crack in a metal wheel, such as the wheel of an aircraft wheel and brake assembly of an aircraft landing gear, a wheel or tire and wheel assembly adapted for use in the method of the invention and a method of forming a wheel adapted for use in the method of the invention.
It is a well established practice in operation of aircraft to conduct regular inspection of components to ensure that they are free from significant defects, including cracks, and are safe for a further period of service. This inspection often necessitates removal of components or assemblies, dismantling and subsequent re-assembly and refitting to the aircraft. Typically the inspection entails a non-destructive type testing procedure, e.g. involving ultrasonic, eddy current or penetrant dye methods, and even in the case of components that do not need to be removed or dismantled for inspection the in situ performance of one of these types of test procedure usually is not convenient.
A particular problem arises in respect of periodic checking of the cast or forged metal wheels of aircraft tire and wheel assemblies to detect any cracks which may be developing. Commonly cracks occur in a part of the wheel which is normally obscured by the tire. Hence checking for cracks generally involves removal of the tire-wheel assembly from the brake assembly and subsequent removal of the tire from the wheel in order that all surfaces of the wheel may be inspected.